5-hydroxypyrazol-4-ylcarbonyl-substituted saccharin derivatives

ABSTRACT

5-Hydroxypyrazol-4-ylcarbonyl-substituted saccharin derivatives of the formula I ##STR1## where the substituents have the following meanings: L and M are hydrogen, C 1  -C 4  -alkyl, C 1  -C 4  -alkoxy, C 1  -C 4  -alkylthio, chlorine, cyano, methylsulfonyl, nitro or trifluoromethyl; 
     Z is hydrogen, C 1  -C 4  -alkyl, C 3  -C 8  -cycloalkyl, C 3  -C 6  -alkenyl, C 3  -C 5  -alkynyl, C 1  -C 4  -acyl, benzyl or phenyl, the phenyl rings in each case being unsubstituted or substituted by halogen or C 1  -C 4  -alkyl; 
     Q is a radical CO--J, 
     J is a 4-linked 5-hydroxypyrazole ring of the formula II ##STR2##  where R  1  is C 1  -C 4  -alkyl and 
     R  2  is hydrogen or methyl, 
     and agriculturally customary salts of the compounds I are described.

This application is a 371 of PCT/EP95/02974 filed Jul. 27, 1995.

The present application relates to5-hydroxypyrazol-4-ylcarbonyl-substituted saccharin derivatives of theformula I ##STR3## where the substituents have the following meanings: Land M are hydrogen, C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy, C₁ -C₄ -alkylthio,chlorine, cyano, methylsulfonyl, nitro or trifluoromethyl;

Z is hydrogen, C₁ -C₄ -alkyl, C₃ -C₈ -cycloalkyl, C₃ -C₆ -alkenyl, C₃-C₅ -alkynyl, C₁ -C₄ -acyl or benzyl or phenyl, each of which isunsubstituted or substituted by halogen or C₁ -C₄ -alkyl;

Q is a radical CO--J,

J is a 4-linked 5-hydroxypyrazole ring of the formula II ##STR4## whereR¹ is C₁ -C₄ -alkyl and

R² is hydrogen or methyl,

and agriculturally customary salts of the compounds I.

The invention further relates to herbicidal compositions, containing theCompounds I, and methods of controlling undesired plant growth using thesaccharin derivatives I.

Saccharin derivatives having herbicidal action cannot be inferred fromthe prior art. However, unsubstituted saccharin (o-sulfobenzimide, ie.L, M, Q and Z in formula I=H) has been known as a synthetic sweetenerfor a long time. 4-Hydroxysaccharin is further known as a sweetener(German Offenlegungsschrift 3 607 343). The use of saccharin derivativesin pest control is also known, eg. JP Publication 72/00419, 73/55457(fungicides) and in pharmacy, eg. EP-A 594 257 and patents furthermentioned therein. Heterocyclic compounds having asulfonamide-containing ring have been disclosed as herbicides, a typicalrepresentative which can be mentioned here being bentazone ##STR5##

It is an object of the present invention to make available novelherbicides having a basic structure which was hitherto unknown for thisindication.

We have found that this object is achieved by the compounds I defined atthe outset.

Compounds of the formula I are obtained by acylating 5-hydroxypyrazolesof the formula II with an acid chloride of the formula IV andrearranging the pyrazole ester formed to give saccharin derivatives ofthe formula I.1, ##STR6##

In the abovementioned formulae, L, M and Z have the meanings given atthe outset.

The first step of the reaction sequence, the acylation, is carried outin a generally known manner, eg. by addition of an acid chloride of theformula IV to the solution or suspension of a 5-hydroxypyrazole II inthe presence of an auxiliary base. The reactants and the auxiliary baseare in this case expediently employed in approximately equimolaramounts. A small excess of the auxiliary base, eg. from 1.2 to 1.5 molequivalents, based on II, can be advantageous in certain circumstances.

Suitable auxiliary bases are tertiary alkylamines, pyridine or alkalimetal carbonates, while the solvents used can be eg. methylene chloride,diethyl ether, toluene or ethyl acetate. During the addition of the acidchloride, the reaction mixture is preferably cooled to 0°-10° C., thenstirred at higher temperature, eg. at 25°-50° C., until the reaction iscomplete.

Working up is carried out in a customary manner, eg. the reactionmixture is poured into water and extracted with methylene chloride.After drying the organic phase and removing the solvent, the crude5-hydroxypyrazole ester can be employed for the rearrangement withoutfurther purification. Preparation examples for benzoic acid esters of5-hydroxypyrazoles are found eg. in EP-A 282 944 or U.S. Pat. No.4,643,757.

The rearrangement of the 5-hydroxypyrazole esters to the compounds ofthe formula 1.1 is expediently carried out at from 20° C. to 40° C. in asolvent and in the presence of an auxiliary base, and with the aid of acyano compound as a catalyst. The solvents used can be eg. acetonitrile,methylene chloride, 1,2-dichloroethane, ethyl acetate or toluene. Thepreferred solvent is acetonitrile. Suitable auxiliary bases are tertiaryalkylamines, pyridine or alkali metal carbonates, which are employed inan equimolar amount or an up to four-fold excess. A preferred auxiliarybase is triethylamine in a doubled amount. Suitable catalysts arecyanide compounds such as potassium cyanide or acetone cyanohydrin, eg.in an amount of from 1 to 50, in particular 5-20, mol %, based on the5-hydroxypyrazole ester. Acetone cyanohydrin is preferably added, eg. inamounts of 10 mol %.

Examples of the rearrangement of benzoic acid esters of5-hydroxypyrazoles are found eg. in EP-A 282 944 or U.S. Pat. No.4,643,757, but there only potassium carbonate or sodium carbonate indioxane is used as a catalyst. The use of potassium cyanide or acetonecyanohydrin is indeed known in connection with the similar rearrangementof enol esters of cyclohexane-1,3-diones (U.S. Pat. No. 4,695,673), butno examples are known from the literature in which cyanide compounds areparticularly highly suitable for the Fries rearrangement of O-acylderivatives of 5-hydroxypyrazole.

Working up is carried out in a customary manner, eg. the reactionmixture is acidified with dilute mineral acids such as 5% hydrochloricacid or sulfuric acid and extracted, eg. with methylene chloride orethyl acetate. For purification, the extract is extracted with cold5-10% strength alkali metal carbonate solution, the final productpassing into the aqueous phase. The product of the formula I isprecipitated by acidifying the aqueous solution, or extracted again withmethylene chloride, dried and then freed from the solvent.

The 5-hydroxypyrazoles of the formula II used as a starting material areknown and can be prepared by processes known per se (cf. EP-A 240 001and J. Prakt. Chem. 315 (1973), 382). 1,3-Dimethyl-5-hydroxypyrazole isa commercially available compound.

The starting substances of the formula IV are prepared in a manner knownper se by reaction of the saccharincarboxylic acid III ##STR7## withthionyl chloride.

Saccharincarboxylic acids III are known in some cases (4-COOH: Zincke,Liebigs Ann. 427 (1922), 231, 5-COOH: Jacobsen, Chem. Ber. 13 (1880),1554, 6-COOH: Weber, Chem. Ber. 25 (1892), 1740). Further, thepreparation of 4-chlorosaccharin-5-carboxylic acid is described inGerman Offenlegungsschrift 3 607 343.

Saccharincarboxylic acids can also be obtained by reacting correspondingbromo- or iodo-substituted saccharin derivatives of the formula A1##STR8## where L, M and Z have the abovementioned meanings, or if Z≠H,compounds of the formula A2 ##STR9## with carbon monoxide and water or aC₁ -C₆ -alcohol at elevated pressure in the presence of a palladium,nickel, cobalt or rhodium transition metal catalyst and a base.

Iodosaccharins are already known from the literature: 6-iodosaccharin:De Roode, Amer. Chem. Journal 13 (1891), 231. They are obtained eitherby permanganate oxidation of iodo-substituted2-methylbenzenesulfonamides or from aminosaccharins by Sandmeyerreaction. Aminosaccharins are obtained by known methods by reduction ofnitrosaccharins, which in turn are either known (Kastle, Amer. Chem.Journal 11 (1889), 184 or DRP 551423.(1930)) or are synthesized in amanner known from the literature from suitable nitrobenzene derivatives(Liebigs Ann. 669 (1963), 85) or nitrobenzenesulfonamides.

If, for example, L is methyl and M and Z are hydrogen, the reactionsequence can be shown as follows: ##STR10##

The catalysts nickel, cobalt, rhodium and in particular palladium can bepresent in metallic form or in the form of customary salts, such as inthe form of halogen compounds, eg. PdCl₂, RhCl₃.H₂ O, acetates, eg.Pd(OAc)₂, cyanides etc. in the known valency states. Metal complexeswith tertiary phosphines, metal alkylcarbonyls, metal carbonyls, eg. CO₂(CO)₈, Ni(CO)₄, metal carbonyl complexes with tertiary phosphines, eg.(PPh₃)₂ Ni(CO)₂, or transition metal salts complexed with tertiaryphosphines can further be present. The last-mentioned embodiment isparticularly preferred in the case of palladium as a catalyst. Thenature of the phosphine ligands here is widely variable. For example,they can be represented by the following formulae: ##STR11## where n isthe numbers 1, 2, 3 or 4 and the radicals R¹ to R⁴ are low-molecularweight alkyl, eg. C₁ -C₆ -alkyl, aryl or C₁ -C₄ -alkylaryl, eg. benzyl,phenethyl or aryloxy. Aryl is, eg. naphthyl, anthryl and preferablyunsubstituted or substituted phenyl, it only being necessary withrespect to the substituents to take into account their inertness to thecarboxylation reaction, otherwise they can be widely varied and includeall inert C-organic radicals such as C₁ -C₆ -alkyl radicals, eg. methyl,carboxyl radicals such as COOH, COOM (M is eg. an alkali metal, alkalineearth metal or ammonium salt), or C-organic radicals bonded via oxygen,such as C₁ -C₆ -alkoxy radicals.

The preparation of the phosphine complexes can be carried out in amanner known per se, eg. as described in the documents mentioned at theoutset. For example, customary commercially available metal salts suchas PdCl₂ or Pd(OCOCH₃)₂ are used as starting materials and thephosphine, eg. P(C₆ H₅)₃, P(n-C₄ H₉)₃, PCH₃ (C₆ H₅)₂ or1,2-bis(diphenylphosphino)ethane, is added.

The amount of phosphine, based on the transition metal, is customarilyfrom 0 to 20, in particular from 0.1 to 10, mol equivalents,particularly preferably from 1 to 5 mol equivalents.

The amount of transition metal is not critical. For cost reasons, ofcourse, rather a small amount, eg. from 0.1 to 10 mol %, in particularfrom 1 to 5 mol %, based on the starting substance A1 or A2, will beused.

Reaction with carbon monoxide and at least equimolar amounts of water,based on the starting substances A1 or A2, is carried out to prepare thesaccharincarboxylic acids III. The reaction component water cansimultaneously also be used as a solvent, ie. the maximum amount is notcritical.

However, it can also be advantageous, depending on the nature of thestarting substances and the catalysts used, to use another inert solventor the base used for the carboxylation as a solvent instead of thereaction component.

Suitable inert solvents for carboxylation reactions are customarysolvents such as hydrocarbons, eg. toluene, xylene, hexane, pentane,cyclohexane, ethers, eg. methyl tert-butyl ether, tetrahydrofuran,dioxane, dimethoxyethane, substituted amides such as dimethylformamide,persubstituted ureas such as tetra-C₁ -C₄ -alkylureas, or nitriles suchas benzonitrile or acetonitrile.

In a preferred embodiment of the process, one of the reactioncomponents, in particular the base, is used in an excess such that noadditional solvent is necessary.

Bases suitable for the process are all inert bases which are able tobind the hydrogen iodide or hydrogen bromide liberated in the reaction.Examples which can be mentioned here are tertiary amines such astriethylamine, cyclic amines such as N-methylpiperidine orN,N'-dimethylpiperazine, pyridine, alkali metal or alkaline earth metalhydroxides, carbonates or hydrogen carbonates, or tetraalkyl-substitutedurea derivatives such as tetra-C₁ -C₄ -alkylurea, eg. tetramethylurea.

The amount of base is not critical, from 1 to 10, in particular from 1to 5, mol customarily being used. When the base is simultaneously usedas a solvent, as a rule the amount is proportioned such that thereaction components are dissolved, unnecessarily high excesses beingavoided for reasons of practicability in order to save costs, to be ableto employ small reaction vessels and to guarantee maximum contact of thereaction components.

During the reaction, the carbon monoxide pressure is adjusted such thatan excess of CO, based on A1 or A2, is always present. Preferably, thecarbon monoxide pressure at room temperature is from 1 to 250 bar, inparticular from 5 to 150 bar, of CO.

As a rule, the carbonylation is carried out continuously or batchwise atfrom 20° to 250° C., in particular at from 30° to 150° C. In the case ofbatchwise operation, carbon monoxide is expediently injected into thereaction mixture continuously to maintain a constant pressure.

The products can be isolated from the resulting reaction mixture in acustomary manner, eg. by distillation.

The starting substances A1 and A2 required for the reaction are known orcan be prepared in a manner known per se, eg. as described in the citedprior art. Moreover, they can be obtained in a similar manner to thepreparation procedures of Examples 1 to 12.

With respect to the intended use, saccharin derivatives of the formula Iare preferred where the radicals L and M are hydrogen, methyl, methoxy,methylthio, chlorine, cyano, methylsulfonyl, nitro or trifluoromethyl.Further, L and M are preferably hydrogen, C₁ -C₄ -alkyl and chlorine.Compounds I are furthermore preferred where L and M are hydrogen or oneof the radicals L or M is hydrogen and the other is methyl or chlorine.

The radical R¹ in formula I is preferably methyl and R² is preferablyhydrogen or methyl.

The radical Z is particularly preferably one of the organic radicalsmentioned, in particular methyl, ethyl, propargyl, acetyl or phenyl.

Particularly preferred active compounds can be taken from Table 1. Thegroups mentioned for a substituent in Table 1 are additionallyconsidered per se, independently of the specific combination with othersubstituents in which they are mentioned, to be a particularly preferreddefinition of the substituent concerned.

The compounds I can be present in the form of their agriculturallyutilizable salts, the nature of the salt in general not mattering.Customarily, the salts of those bases which do not adversely affect theherbicidal action of I will be suitable.

Suitable basic salts are particularly those of the alkali metals,preferably the sodium and potassium salts, those of the alkaline earthmetals, preferably calcium, magnesium and barium salts and those of thetransition metals, preferably manganese, copper, zinc and iron salts aswell as the ammonium salts, which can carry one to three C₁ -C₄ -alkylor hydroxy-C₁ -C₄ -alkyl substituents and/or a phenyl or benzylsubstituent, preferably diisopropylammonium, tetramethylammonium,tetrabutylammonium, trimethylbenzylammonium andtrimethyl-(2-hydroxyethyl)ammonium salts, the phosphonium salts, thesulfonium salts, preferably tri(C₁ -C₄)-alkylsulfonium salts, and thesulfoxonium salts, preferably tri(C₁ -C₄)-alkylsulfoxonium salts.

The compounds or the herbicidal compositions containing them and theirenvironmentally tolerable salts of, for example, alkali metals, alkalineearth metals or ammonia and amines or the herbicidal compositionscontaining them can control broad-leaved weeds and grass weeds highlyeffectively in crops such as wheat, rice, maize, soybeans and cottonwithout noticeably damaging the crop plants. This effect occursespecially at low application rates.

Taking into account the versatility of the application methods, thecompounds or compositions containing them can also be employed in afurther number of crop plants for the elimination of undesired plants.Examples of suitable crops are the following: Allium cepa, Ananascomosus, Arachis hypogaea, Asparagus officinalis, Beta vulgaris spp.altissima, Beta vulgaris spp. rapa, Brassica napus var. napus, Brassicanapus var. napobrassica, Brassica rapa var. silvestris, Camelliasinensis, Carthamus tinctorius, Carya illinoinensis, Citrus limon,Citrus sinensis, Coffea arabica (Coffea canephora, Coffea liberica),Cucumis sativus, Cynodon dactylon, Daucus carota, Elaeis guineensis,Fragaria vesca, Glycine max, Gossypium hirsutum, (Gossypium arboreum,Gossypium herbaceum, Gossypium vitifolium), Helianthus annuus, Heveabrasiliensis, Hordeum vulgare, Humulus lupulus, Ipomoea batatas, Juglansregia, Lens culinaris, Linum usitatissimum, Lycopersicon lycopersicum,Malus spp., Manihot esculenta, Medicago sativa, Musa spp., Nicotianatabacum (N. rustica), Olea europaea, Oryza sativa, Phaseolus lunatus,Phaseolus vulgaris, Picea abies, Pinus spp., Pisum sativum, Prunusavium, Prunus persica, Pyrus communis, Ribes sylvestre, Ricinuscommunis, Saccharum officinarum, Secale cereale, Solanum tuberosum,Sorghum bicolor (S. vulgare), Theobroma cacao, Trifolium pratense,Triticum aestivum, Triticum durum, Vicia faba, Vitis vinifera, Zea mays.

Moreover, the compounds can also be employed in crops which have beenmade largely resistant to the action of I or other herbicides bybreeding and/or by means of genetic engineering methods.

The application of the herbicidal compositions or of the activecompounds can be carried out preemergence or postemergence. If theactive compounds are less tolerable for certain crop plants, applicationtechniques can be used in which the herbicidal compositions are sprayedwith the aid of the spray equipment such that the leaves of thesensitive crop plants are not affected if possible, while the activecompounds reach the leaves of undesired plants growing under them or theuncovered soil surface (post-directed, lay-by).

The compounds or the herbicidal compositions containing them can beapplied by spraying, atomizing, dusting, scattering or watering, forexample in the form of directly sprayable aqueous solutions, powders,suspensions, even high-percentage aqueous, oily or other suspensions ordispersions, emulsions, oil dispersions, pastes, dusting compositions,scattering compositions or granules. The application forms depend on theintended uses; if possible they should in each case guarantee the finestdispersion of the active compounds according to the invention.

Suitable inert auxiliaries for the preparation of directly sprayablesolutions, emulsions, pastes or oil dispersions are essentially: mineraloil fractions of medium to high boiling point such as kerosene or dieseloil, further coal tar oils and oils of vegetable or animal origin,aliphatic, cyclic and aromatic hydrocarbons, eg. paraffins,tetrahydronaphthalene, alkylated naphthalenes or their derivatives,alkylated benzenes and their derivatives, alcohols such as methanol,ethanol, propanol, butanol and cyclohexanol, ketones such ascyclohexanone or strongly polar solvents, eg. amines such asN-methylpyrrolidone, or water.

Aqueous application forms can be prepared from emulsion concentrates,suspensions, pastes, wettable powders or water-dispersable granules byaddition of water. To prepare emulsions, pastes or oil dispersions, thesubstrates can be homogenized in water, as such or dissolved in an oilor solvent, by means of wetting agents, adhesives, dispersants oremulsifiers. However, concentrates consisting of active substance,wetting agent, adhesive, dispersant or emulsifier and possibly solventor oil which are suitable for dilution with water can also be prepared.

Suitable surface-active substances are the alkali metal, alkaline earthmetal or ammonium salts of aromatic sulfonic acids, eg. lignosulfonic,phenolsulfonic, naphthalenesulfonic and dibutylnaphthalenesulfonic acid,as well as of fatty acids, alkyl- and alkylarylsulfonates, alkyl-,lauryl ether and fatty alcohol sulfates, and also salts of sulfatedhexa-, hepta- and octadecanols as well as of fatty alcohol glycolethers, condensation products of sulfonated naphthalene and itsderivatives with formaldehyde, condensation products of naphthalene orof the naphthalenesulfonic acids with phenol and formaldehyde,polyoxyethylene octyl phenol ethers, ethoxylated isooctyl-, octyl- ornonylphenol, alkylphenyl or tributylphenylpolyglycol ethers, alkylarylpolyether alcohols, isotridecyl alcohol, fatty alcohol-ethylene oxidecondensates, ethoxylated castor oil, polyoxyethylene or polyoxypropylenealkyl ethers, lauryl alcohol polyglycol ether acetate, sorbitol esters,lignin-sulfite waste liquors or methylcellulose.

Powder, scattering and dusting compositions can be prepared by mixing orjoint grinding of the active substances with a solid carrier.

Granules, eg. coated, impregnated and homogeneous granules can beprepared by binding of the active compounds to solid carriers. Solidcarriers are mineral earths such as silicic acids, silicates, talc,kaolin, limestone, lime, chalk, bole, loess, clay, dolomite,diatomaceous earth, calcium sulfate and magnesium sulfate, magnesiumoxide, ground synthetic materials, fertilizers, such as ammoniumsulfate, ammonium phosphate, ammonium nitrate, ureas and vegetableproducts such as cereal flour, tree bark meal, wood meal and nutshellmeal, cellulose powder or other solid carriers.

In general, the formulations contain from 0.01 to 95% by weight,preferably from 0.5 to 90% by weight, of active compound. The activecompounds are employed here in a purity of from 90% to 100%, preferablyfrom 95% to 100% (according to NMR spectrum). The compounds I accordingto the invention can be formulated, for example, as follows:

I. 20 parts by weight of the compound I are dissolved in a mixture whichconsists of 80 parts by weight of alkylated benzene, 10 parts by weightof the addition product of from 8 to 10 mol of ethylene oxide to 1 molof oleic acid N-monoethanolamide, 5 parts by weight of calcium salt ofdodecylbenzenesulfonic acid and 5 parts by weight of the additionproduct of 40 mol of ethylene oxide to 1 mol of castor oil. By pouringout the solution and finely dispersing it in 100,000 parts by weight ofwater, an aqueous dispersion is obtained which contains 0.02% by weightof the active compound.

II. 20 parts by weight of the compound I are dissolved in a mixturewhich consists of 40 parts by weight of cyclohexanone, 30 parts byweight of isobutanol, 20 parts by weight of the addition product of 7mol of ethylene oxide to 1 mol of isooctylphenol and 10 parts by weightof the addition product of 40 mol of ethylene oxide to I mol of castoroil. By pouring the solution into and finely dispersing it in 100,000parts by weight of water, an aqueous dispersion is obtained whichcontains 0.02% by weight of the active compound.

III. 20 parts by weight of the active compound I are dissolved in amixture which consists of 25 parts by weight of cyclohexanone, 65 partsby weight of a mineral oil fraction of boiling point from 210° to 280°C. and 10 parts by weight of the addition product of 40 mol of ethyleneoxide to 1 mol of castor oil. By pouring the solution into and finelydispersing it in 100,000 parts by weight of water, an aqueous dispersionis obtained which contains 0.02% by weight of the active compound.

IV. 20 parts by weight of the active compound I are thoroughly mixedwith 3 parts by weight of the sodium salt ofdiisobutylnaphthalene-α-sulfonic acid, 17 parts by weight of the sodiumsalt of a lignosulfonic acid from a sulfite waste liquor and 60 parts byweight of powdered silica gel and ground in a hammer mill. By finelydispersing the mixture in 20,000 parts by weight of water, a spraymixture is obtained which contains 0.1% by weight of the activecompound.

V. 3 parts by weight of the active compound I are mixed with 97 parts byweight of finely divided kaolin. In this way, a dusting composition isobtained which contains 3% by weight of the active compound.

VI. 20 parts by weight of the active compound I are intimately mixedwith 2 parts by weight of calcium salt of dodecylbenzenesulfonic acid, 8parts by weight of fatty alcohol polyglycol ether, 2 parts by weight ofsodium salt of a phenol-urea-formaldehyde condensate and 68 parts byweight of a paraffinic mineral oil. A stable oily dispersion isobtained.

To widen the spectrum of action and to achieve synergistic effects, thesaccharincarboxylic acid derivatives can be mixed with numerousrepresentatives of other herbicidal or growth-regulating active compoundgroups and applied jointly. For example, suitable mixture components arediazines, 4H-3,1-benzoxazine derivatives, benzothiadiazinones,2,6-dinitroanilines, N-phenylcarbamates, thiocarbamates, halocarboxylicacids, triazines, amides, ureas, diphenyl ethers, triazinones, uracils,benzofuran derivatives, cyclohexane-1,3-dione derivatives which carryeg. a carboxyl or carbimino group in the 2-position, quinolinecarboxylicacid derivatives, imidazolinones, sulfonamides, sulfonylureas, aryloxy-or heteroaryloxyphenoxypropionic acids and their salts, esters andamides and others.

Additionally, it may be useful to apply the compounds I on their own ortogether in combination with other herbicides, additionally mixed withfurther crop protection agents, for example with agents for controllingpests or phytopathogenic fungi and bacteria. Further of interest is themiscibility with mineral salt solutions, which are employed for theelimination of nutritional and trace element deficiencies. Nonphytotoxicoils and oil concentrates can also be added.

Depending on the aim of control, time of year, target plants and stageof growth, the application rates of active compound are from 0.001 to3.0, preferably from 0.01 to 1.0, kg/ha of active substance (a.s.).

PREPARATION EXAMPLES 1. 2-Methyl-6-acetamidobenzoic acid

90.6 g (0.6 mol) of 6-methylanthranilic acid are added to a solution of24.8 g (0.62 mol) of NaOH in 500 ml of water and 63.4 g (0.62 mol) ofacetic anhydride are then added dropwise. After stirring for one hour,the mixture is acidified to pH 3 with conc. HCl with cooling, and theprecipitate which deposits is filtered off with suction, washed withwater and dried under reduced pressure at 50° C.

Yield: 107 g (0.55 mol)=92% of theory, m.p.: 189°-190° C.

2. 2-Methyl-3-nitro-6-acetamidobenzoic acid

271 ml of 98% nitric acid are initially taken at -5° C. and 106 g (0.55mol) of the 2-methyl-6-acetamidobenzoic acid prepared in 1. are added inportions. After stirring at 10° C. for one hour, the reaction mixture ispoured into a mixture of 540 g of ice and 270 ml of water. The depositedprecipitate is filtered off with suction, washed with water and driedunder reduced pressure at 50° C.

Yield: 75.6 g (0.317 mol)=58% of theory, m.p.: 190°-191° C.

The isomer nitrated in the 3-position is deposited from the filtrateafter relatively long standing:

Yield: 21.3 g (0.089 mol)=16% of theory, m.p.: 180°-182° C.

3. 2-Methyl-3-nitro-6-aminobenzoic acid

450 ml of 2N NaOH are initially taken and 75.6 g (0.317 mol) of2-methyl-3-nitro-6-acetamidobenzoic acid are added. The reaction mixtureis then warmed to 95° C. and is stirred at this temperature for onehour. After cooling to 10° C., it is acidified by addition of 425 ml of2N HCl, and the precipitate which deposits is filtered off with suction,washed with water and dried under reduced pressure at 50° C.

Yield: 50.7 g (0.258 mol)=82% of theory, m.p.: 183°-184° C.

4. Methyl 2-methyl-3-nitro-6-aminobenzoate

49.7 g (0.253 mol) of 2-methyl-3-nitro-6-aminobenzoic acid are dissolvedin 380 ml of acetone and 43 g (0.51 mol) of sodium hydrogen carbonateare added. The mixture is then heated to boiling until evolution of CO₂is complete. 35.3 g (0.28 mol) of dimethyl sulfate are then addeddropwise in the course of two hours at the boiling point of acetone tothe suspension of the sodium salt of 2-methyl-3-nitro-6-aminobenzoicacid thus obtained, and the mixture is subsequently refluxed for afurther three hours and then allowed to cool. After pouring the reactionmixture into 1.8 l of water, it is extracted with methylene chloride.After drying the organic phase, it is concentrated. The solid obtainedis sufficiently pure for the subsequent reaction (NMR).

Yield: 50 g (0.238 mol)=94% of theory, m.p.: 92°-94° C.

5. 2-Methoxycarbonyl-3-methyl-4-nitrobenzenesulfonyl chloride

58.5 g (0.278 mol) of methyl 2-methyl-3-nitro-6-aminobenzoate aredissolved with warming in 280 ml of glacial acetic acid and thissolution is poured at 15°-20° C. into 85 ml of conc. HCl. A solution of19.3 g (0.28 mol) of sodium nitrite in 60 ml of water is then addeddropwise at 5°-10° C. and the mixture is stirred at 5° C. for 30 min.This diazonium salt solution is subsequently added dropwise to asolution of 374 g of SO₂ in 750 ml of glacial acetic acid which contains14 g of CuCl₂ (dissolved in 30 ml of water). After completion of theevolution of nitrogen, the mixture is stirred for a further 15 min andthen poured into 1.4 l of ice-water. The sulfonyl chloride is separatedoff by extraction with 1.2 l of methylene chloride. After drying andconcentrating the organic phase, 73 g (0.25 mol) (=90% of theory) of anoil are obtained, which according to NMR (in CDCl₃) is pure2-methoxycarbonyl-3-methyl-4-nitrobenzenesulfonyl chloride.

6. 4-Methyl-5-nitrosaccharin

104 ml of 25% ammonia solution are initially taken, 100 ml of water areadded and a solution of 48.7 g (0.166 mol) of2-methoxycarbonyl-3-methyl-4-nitrobenzenesulfonyl chloride in 70 ml oftetrahydrofuran is then added dropwise at 10° C. After stirring at 25°C. for three hours, the mixture is concentrated on a rotary evaporatorto remove water and THF. The residue which remains is stirred with ethylacetate, filtered off with suction and washed with ethyl acetate. Afterdrying under reduced pressure, 34 g (0.131 mol)=79% of theory of a whitesolid of m.p.: 312° C. (dec.) are obtained.

7. 2,4-Dimethyl-5-nitrosaccharin

This substance can be prepared by subsequent methylation of thesaccharin obtained in 6. using dimethyl sulfate in the presence of NaOH.

8. 3-Methyl-4-nitro-2-(N'-methyl)carboxamido-N-methylbenzenesulfonamide

50 ml of water are poured into 50 ml of 40% methylamine solution and asolution of 24.3 g (83 mmol.) of2-methoxycarbonyl-3-methyl-4-nitrobenzenesulfonyl chloride in 35 ml ofTHF is added dropwise at 10° C. After stirring for one hour at 25° C.,all volatile constituents are removed on a rotary evaporator, theresidue is extracted with ethyl acetate, and the organic phase is washedwith water, dried and concentrated. The residue which remainscrystallizes after relatively long standing.

Yield: 10.3 g (40 mmol=48% of theory), m.p.: 125°-126° C., afterrecrystallization from ethyl acetate m.p.: 144°-145° C.

9. 4-Methyl-5-aminosaccharin

33.6 g (0.13 mol) of 4-methyl-5-nitrosaccharin are dissolved in 1.2 l ofwater with warming to 45° C. and 5 g of Pd/C (10% on active carbon) areadded. Hydrogen gas is then passed in with vigorous stirring(pressureless hydrogenation). 9 l of H₂ are absorbed in the course of4.5 hours. After cooling to 25° C., the catalyst is filtered off, andthe filtrate is concentrated to a volume of 200 ml and then acidified topH 1. The deposited precipitate is filtered off with suction, washedwith water and dried under reduced pressure at 50° C. 23.4 g (0.11mol=85% of theory) of a white solid of m.p.: 272°-273° C. are obtained.

10. 4-Methyl-5-iodosaccharin

A mixture of 205 ml of glacial acetic acid, 160 ml of water and 40 ml ofconc. HCl is initially taken and 23.4 g (0.11 mol) of4-methyl-5-aminosaccharin are introduced with stirring at 15°-20° C. 7.9g (0.115 mol) of sodium nitrite are added dropwise to the resultingsuspension at 5°-10° C. and it is stirred at 5° C. for 30 min. Thediazonium salt, which is present as a suspension, is then added dropwisein portions to a solution of 19.1 g (0.115 mol) of potassium iodide in170 ml of water which is warmed to 50° C., nitrogen being formed. Aftercooling to room temperature, the deposited product is isolated byfiltering off with suction, washed with water and dried under reducedpressure at 50° C. 32.5 g (0.1 mol=91% of theory) of a solid of m.p.:257°-258° C. are obtained. A combustion analysis gave an iodine contentof 38.5% (theory 39.3%).

The product is sufficiently pure for the subsequent reaction.

11.4-Methylsaccharin-5-carboxylic acid

6.4 g (0.002 mol) of 4-methyl-5-iodosaccharin are dissolved in 70 ml oftetramethylurea and 30 ml of water and treated with 0.7 g ofbis(triphenylphosphine)palladium chloride and the mixture is heated to100° C. in a 300 ml autoclave and stirred at a pressure of 100 bar ofcarbon monoxide for 36 h.

For working up, the mixture is filtered, and water and tetramethylureaare removed by distillation in a high vacuum. The residue is taken up inmethyl tert-butyl ether (MTBE), extracted with NaHCO₃ soln. and, afteracidifying with HCl, extracted again with MTBE. After concentrating, 2.8g of 4-methylsaccharin-5-carboxylic acid (58% of theory) are obtained.

¹ H NMR (DMSO, 400.1 MHz): 2.85 (3H, s); 8.05 (1H, d); 8.2 (1H, d);

¹³ C NMR (DMSO, 100.6 MHz): 167.4 (CO); 161.3 (CO); 141.6 (quart. C);139.7 (quart. C); 138.7 (quart. C); 135.6 (CH); 125.4 (quart. C); 118.5(CH); 15.4 (CH₃).

12. 2,4-Dimethylsaccharin-5-carboxylic acid

7.3 g (0.02 mol) of3-methyl-4-iodo-2-(N'-methyl)carboxamido-N-methylbenzenesulfonamide areinitially taken in a 300 ml autoclave, together with 0.69 g ofbis(triphenylphosphine)palladium chloride, 30 ml of water and 70 ml oftetramethylurea, and the mixture is heated to 100° C. and stirred at apressure of 100 bar of carbon monoxide for 36 h.

After working up as described in Example 12, 4.1 g of the title compoundare obtained (0.014 mol=72% of theory).

¹ H NMR (DMSO, 400.1 MHz): 2.9 (3H, s); 3.15 (3H, s); 8.2 (2H, 2d); 14.0(1H, s)

¹³ C NMR (DMSO, 100.6 MHz): 167.3 (CO); 158.6 (CO); 139.7 (quart. C);139.1 (quart. C); 138.9 (quart. C); 135.5 (CH); 124.6 (quart. C); 119.0(CH); 22.9 (CH₃); 15.6 (CH₃).

13. 4-Amino-3-methyl-2-(N'-methyl)carboxamido-N-methylbenzenesulfonamide

In a similar manner to the procedure described in section 9, the3-methyl-4-nitro-2-(N'-methyl)carboxamido-N-methylbenzenesulfonamideobtained in section 8 was hydrogenated without pressure.

The aniline derivative of the following structure of m.p. 217°-218° C.is obtained in 93% yield. ##STR12##

14. 3-Methyl-4-iodo-2-(N'-methyl) carboxamido-N-methylbenzenesulfonamide

The above compound was diazotized according to the procedure describedin section 10 and converted to the iodobenzene derivative of thestructure by reaction with KI. ##STR13##

Yield: 95%, m.p.: 60°-62° C.

15. 2,4-Dimethylsaccharin-5-carbonyl chloride

3.8 g (14.9 mmol) of 2,4-dimethylsaccharin-5-carboxylic acid aresuspended in 100 ml of toluene, and the mixture is warmed to 80° C. and3.5 g (29.8 mmol) of thionyl chloride are added dropwise. Afterrefluxing for two hours, the solution is decanted hot and the reactionmixture is concentrated on a rotary evaporator. The product obtained (3g, 74% of theory) has m.p.: 149°-150° C.

16. General Procedure for the Preparation of the Compounds I 16.1Acylation of 5-hydroxy-1,3-dimethylpyrazole with a saccharincarbonylchloride

1.01 g (11 mmol) of triethylamine are added to a suspension of 1.12 g(10 mmol) of 5-hydroxy-1,3-dimethylpyrazole in 70 ml of methylenechloride. A solution or suspension of 10 mmol of the acid chloride ofthe formula IV in 30 ml of methylene chloride is then added dropwise at25° C. and the reaction mixture is then warmed to 45° C. for 5 hours.After cooling to 25° C., it is treated with 60 ml of water and pouredinto a separating funnel, and the organic phase is separated off. Afterextraction of the aqueous phase with 50 ml of methylene chloride, theorganic phases are combined and dried over sodium sulfate. Afterfiltering and removing the methylene chloride, an oil remains which isused without further purification for the rearrangement.

16.2 Rearrangement of the Pyrazole Ester Obtained in 16.1

The saccharincarboxylic acid O-acyl ester of5-hydroxy-1,3-dimethylpyrazole (about 10 mmol) obtained in 16.1 isinitially taken in 80 ml of acetonitrile and first treated with 2.7 ml(2.2 g=20 mmol) of triethylamine, then with 0.2 g (2.3 mmol) of acetonecyanohydrin and the reaction mixture is stirred at 25° C. for 16 hours.30 g of 5% HCl are then poured into the reaction mixture and it isextracted with methylene chloride. The organic phase is then extractedwith 5% potassium carbonate solution, the organic phase is discarded andthe alkaline-aqueous phase is acidified to pH 1 by dropwise addition ofconc. HCl, the product precipitating as a viscous mass. Forpurification, the product is dissolved in methylene chloride, and thesolution is washed with water, dried over sodium sulfate andconcentrated. By rubbing with diethyl ether/petroleum ether, the residuebecomes crystalline. The compounds compiled in Table 1 can be obtainedin a similar manner:

                  TABLE 1                                                         ______________________________________                                         ##STR14##                                                                    No.  R.sup.1                                                                              R.sup.2                                                                              Q-Pos.                                                                              L     M     Z      M.p. (°C.)                 ______________________________________                                        1.01 CH.sub.3                                                                             H      4     H     H     H                                        1.02 CH.sub.3                                                                             CH.sub.3                                                                             4     H     H     H                                        1.03 C.sub.2 H.sub.5                                                                      H      4     H     H     CH.sub.3                                 1.04 CH.sub.3                                                                             H      4     H     H     C.sub.2 H.sub.5                          1.05 CH.sub.3                                                                             H      4     H     H     C.sub.6 H.sub.5                          1.06 CH.sub.3                                                                             H      5     4-CH.sub.3                                                                          H     H                                        1.07 CH.sub.3                                                                             H      5     4-Cl  H     H                                        1.08 CH.sub.3                                                                             CH.sub.3                                                                             5     H     4-CH.sub.3                                                                          CH.sub.3                                 1.09 CH.sub.3                                                                             CH.sub.3                                                                             5     H     4-Cl  C.sub.2 H.sub.5                          1.10 C.sub.2 H.sub.5                                                                      H      5     H     H     Propargyl                                1.11 CH.sub.3                                                                             H      6     H     H     CH.sub.3                                 1.12 CH.sub.3                                                                             H      6     4-CH.sub.3                                                                          H     H                                        1.13 CH.sub.3                                                                             H      6     4-Cl  H     H                                        1.14 CH.sub.3                                                                             CH.sub.3                                                                             6     H     4-CH.sub.3                                                                          CH.sub.3                                 1.15 CH.sub.3                                                                             CH.sub.3                                                                             6     H     4-Cl  CH.sub.3                                 ______________________________________                                    

USE EXAMPLES

It was possible to show the herbicidal action of the saccharinderivatives of the formula I by greenhouse tests:

The cultivation vessels used were plastic flowerpots containing loamysand with about 3.0% humus as a substrate. The seeds of the test plantswere sown separately according to species.

In the case of preemergence treatment, the active compounds suspended oremulsified in water were applied directly after sowing by means offinely dispersing nozzles. The vessels were lightly watered in order topromote germination and growth, and then covered with transparentplastic hoods until the plants had taken root. This covering causes auniform germination of the test plants if this was not adverselyaffected by the active compounds.

For the purpose of postemergence treatment, the test plants were firstraised, according to growth form, to a height of growth of from 3 to 15cm and only then treated with the active compounds suspended oremulsified in water. For this purpose, the test plants were either sowndirectly and raised in the same vessels or they were first raisedseparately as seedlings and transplanted into the test vessels a fewdays before the treatment.

The plants were kept species-specifically at 10°-25° C. or 20°-35° C.The test period extended over 2 to 4 weeks. During this time, the plantswere tended and their reaction to the individual treatments wasassessed.

Rating was carried out on a scale of from 0 to 100. 100 in this casemeans no emergence of the plants or complete destruction of at least theabove-ground parts and 0 means no damage or normal course of growth.

We claim:
 1. A 5-hydroxypyrazol-4-ylcarbonyl-substituted saccharinderivative of the formula I ##STR15## where the substituents have thefollowing meanings: L and M are hydrogen, C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy,C₁ -C₄ -alkylthio, chlorine, cyano, methylsulfonyl, nitro ortrifluoromethyl;Z is hydrogen, C₁ -C₄ -alkyl, C₃ -C₈ -cycloalkyl, C₃ -C₆-alkenyl, C₃ -C₅ -alkynyl, C₁ -C₄ -acyl, benzyl or phenyl, the phenylrings in each case being unsubstituted or substituted by halogen or C₁-C₄ -alkyl; Q is a radical CO--J, J is a 4-linked 5-hydroxypyrazole ringof the formula II ##STR16## where R¹ is C₁ -C₄ -alkyl and R² is hydrogenor methyl, and agriculturally customary salts of the compounds I.
 2. Asaccharin derivative of the formula I as claimed in claim 1, where theradicals L and M are hydrogen, C₁ -C₄ -alkyl or chlorine.
 3. A saccharinderivative of the formula I as claimed in claim 1, where the radicals Land M are hydrogen, methyl, methoxy, methylthio, chlorine, cyano,methylsulfonyl, nitro or trifluoromethyl.
 4. A herbicidal composition,containing at least one saccharin derivative of the formula I as claimedin claim 1 and customary inert additives.
 5. A method of controllingundesired plant growth, which comprises allowing a herbicidally activeamount of a saccharin derivative of the formula I as claimed in claim 1to act on the plants or their habitat.
 6. A process for preparing thecompounds of the formula I as claimed in claim 1, which comprisesacylating 5-hydroxypyrazoles of the formula II ##STR17## where R¹ is C₁-C₄ -alkyl andR² is hydrogen or methyl, with an acid chloride of theformula IV ##STR18## where L, M and Z have the meanings mentioned inclaim 1, and rearranging the acylation product to the compounds I in thepresence of a catalyst.